Memcached::increment

Descrierea

Memcached::increment() increments a numeric item's value
by the specified offset. If the item's value is not
numeric, an error will result.
Memcached::increment() will set the item to the
initial_value parameter if the key doesn't exist.

If it'll save others some head-scratching, the PECL Memcached extension only supports initializing increment (or decrement) values from 2.0.0b2 onwards - i.e. not the version (1.0.2) that comes out of the box with Ubuntu 12.04.